We never got to see the Brady Bunch family celebrate Halloween, per se, but they did get into the spirit on occassion with a few fright-themed episodes.
TO MOVE OR NOT TO MOVE (Season 1, 1970)
In a plot as old as television, the Brady kids haunt their own house to scare away prospective buyers when dad Mike decides its time to move.
We start with a little foreshadowing, as maid Alice tells Carol Brady that the old Macintyre house has been on the market for years because it's allegedly haunted. Voices in the night..chains rattling...lights going on and off..!
Later that evening, Carol is frightened as "inhuman" noises are heard from outside the house.
The next night, Bobby and Cindy run down the stairs after hearing mysterious creakings.
That old Brady house give me the creeps....
Finally the source of the sounds is revealed: the Brady kids. In a secret meeting, we learn all the kids haunting duties. Greg is in charge of the tape recorder with the unexplained noises; Peter handles white sheets and ghostly appearances; Jan and Marcia are in charge of slamming doors and windows; and little Bobby and Cindy will coordinate with Peter for "spectral duties".
Once Mrs. Hunzinger arrives and the spook-team goes into action, we get a rare peek into Alice's world when we learn she has a Ghost-B-Gone Anti-Witch Charm.
Luckily Mike comes home from work in time to put a stop to the shenanigans, uncloaking Bobby and Cindy in their ghost costumes.
THE SLUMBER CAPER (Season 2, 1970)
Our next scary entry centers on Marcia's first sleepover party. The boys aren't thrilled at first, until they hatch a plot to unleash a few spooky tricks on the unsuspecting girls.
"Rubber spiders! Scary masks! Spooky noisemakers! Plastic skeletons! And itching powder in the sleeping bags!"
The party in progress, the girls settle down for a little Truth or Dare.
Marcia and previously-never-heard-of-and-never-seen-again-after-this-episode friend Ruthie are dared to sneak up and spy on the boys, only to be intercepted on the stairs by Greg in costume.
Alice suspects mischief and warns "If the werewolf howls, or the vampire starts flapping its wing, don't come running to me."
Jan is telling a ghost story when the itching powder the boys have put in the sleeping bags starts to kick in.
The next morning, the spirit of the party lingers on as Mike discovers another spider in a box of cookies.
FRIGHT NIGHT (Season 4, 1972)
My favorite of the scary Brady episodes starts off with a bang as the girls are awakened by a mysterious apparition outside their window.
Mike and Carol comfort the girls and insist they must have dreamed the incident.
The boys, on the other hand, are in their own room, celebrating their prank.
It doesn't take long for the girls to suspect trickery. After snooping through the boys room, they find the evidence: a slide projector and slides of Peter in ghost get-up.
They goad the boys into a bet that they aren't brave enough to spend the night in the attic.
The unsuspecting boys settle down for the night, only to be awakened by a creepy voice coming from on old trunk. "I'm burning up... I'm burning up...!"
A celophane phantom, controlled by Marcia in another room, rises out of the trunk, sending Bobby and Peter scampering downstairs, thereby losing the bet.
Discussing the bet later with Alice, in a bizarre change of character, Alice says "Anybody who believes in ghosts is a sucker!" So much for her Ghost-B-Gone.
In a key piece of exposition, we learn that Carol is taking a sculpting class and has made a life-like bust of husband Mike to enter in an art contest.
Moving on, the kids decide to challenge Alice's bravery by launching a full scale fright assault when she returns to the house late that night. We see each stage of the preparation.
Greg sets up his plastic skull.
The girls assemble the ghost.
The ghost is wired to float down the stairs.
Finally, its showtime. The lights have been shut off and the kids lie in wait as Alice comes home. But wait...it's not Alice at all, but Mike and Carol, with her prize-winning bust.
They don't seem too impressed by the scary spectacle, and Mike sets about getting the lights back on.
Only then does Alice finally come home.